Age-related macular degeneration affects approximately 20% of those over the age of 55. In many patients, the disease causes blood vessels within the eye to grow, bleed, and then scar, resulting in severe and disabling loss of vision. Conventional treatment currently consists of regular injection into the eye, every 4-6 weeks, of drugs, such as LUCENTIS® or AVASTIN®. Such injections must be made precisely to avoid damage to various parts of the eye. In reference to FIG. 1, the drug should be delivered into the vitreous cavity, or chamber, 2 of a patient's eye 3, which is filled with the vitreous humor 4—a clear gel-like substance. To enter the vitreous cavity safely, the needle of a syringe must pass through the sclera (the white of the eye) 5 via the pars plana 6. The pars plana is a ring-shaped zone, which is defined by two imaginary circles that are situated about three and five millimeters, respectively, outside the edge of the cornea 7 of eye 3, as schematically illustrated in FIG. 2. Referring again to FIG. 1, a needle that is inserted through the pars plana and directed appropriately will pass between the lens 8 and the retina 9, thereby avoiding injury to both structures. Currently, to make these injections, retina specialists use one hand to hold the patient's eye open and steady. The other hand is then used to, first, insert the needle of a syringe into the appropriate location at an appropriate angle and to an appropriate depth in the eye, and then second, press the plunger of the syringe to inject the drug into the eye. Finally, the needle is withdrawn from the eye.
Injection of a substance into and/or extraction of a substance from an eye may be performed for various reasons, including, but not limited to, one or more of the treatment of macular degeneration, diabetic retinopathy, uveitis, infections, inflammations, etc.